ABSTRACT
In one way or another, almost any vibrating system could be modelled and represented as an SDOF system. In general, the quality of this assumption depends on the type of system and excitation, on the accuracy required and on the scope of the investigation. In some circumstances the assumption is correct; in some other cases it may lead to a description of the system’s dynamic behaviour within an acceptable degree of accuracy but, in many other cases, the assumption is just an extreme oversimplification leading to inaccurate results which have almost nothing to do with the real situation. Since, a priori, the true behaviour of a real system is in general not known, the assessment of the validity of the results obtained from a SDOF analysis may not be an easy task. Therefore, in order to obtain a meaningful description for a wide class of systems, more complex representations are needed from the outset.
